System for touch pad

ABSTRACT

Provided is a system for a touch pad used by both a finger and a pen to input operations to a computer. The system includes a sensor electrode group, an integrated circuit, and a memory storing a device driver. The sensor electrode group is configured to be placed over a touch surface that is different from a display surface of the computer. The integrated circuit uses the sensor electrode group to detect a touch position on the touch surface where the finger is in contact and a pen position on the touch surface where the pen is in contact and supplies the detected touch position and pen position to the device driver. The device driver is configured to convert the touch position into relative coordinates when the device driver receives the touch position, and convert the pen position into absolute coordinates when the device driver receives the pen position.

BACKGROUND Technical Field

The present disclosure relates to a system for touch pad, andparticularly, to a system for touch pad used by both a finger and a pento input operations to a computer.

Background Art

There is a known input system that uses a sensor electrode group placedover a display apparatus to detect contact positions of a pen and afinger on a display surface in time division and that supplies thecontact positions to an operating system. An example of theabove-described input system is disclosed in Japanese Patent No.6473554. The positions supplied to the operating system are used tocontrol movement of a cursor or to input a line drawing to a drawingapplication.

The data actually supplied from this type of input system to theoperating system usually includes coordinates in a coordinate system ofthe display surface. For example, two-dimensional coordinates (x, y) ofthe rectangular display surface decided with the long side as the x-axisand the short side as the y-axis are supplied as a contact position ofthe pen or the finger to the operating system. Hereinafter, thecoordinates in the coordinate system of a surface in this way will bereferred to as “absolute coordinates.”

Some notebook personal computers and the like include input systemscalled touch pads. The touch pad is an apparatus including a plane(hereinafter, referred to as a “touch surface”) on which a user canslide a finger. The touch pad is configured to detect a contact positionof the finger (hereinafter, referred to as a “touch position”) on thetouch surface and supply the touch position to the operating system. Anexample of the touch pad is disclosed in U.S. Pat. No. 9,207,801.

The data actually supplied from the touch pad to the operating system isusually data indicating the distance and the direction of movement ofthe touch position. For example, coordinates (x_(N)-x_(O), y_(N)-y_(O))indicating a vector ending at a touch position (x_(N), y_(N)) detectedat certain time and starting at a touch position (x_(O), y_(O)) detectedjust before the touch position (x_(N), y_(N)) are supplied as dataindicating the touch position of the finger to the operating system.Hereinafter, the data indicating the distance and the direction ofmovement of the touch position will be referred to as “relativecoordinates.” Note that when there is no coordinate as a start point(that is, just after the finger has touched the touch surface), the datais not supplied to the operating system. By using the relativecoordinates, the user can use a finger to repeatedly trace the sameregion on the relatively narrow touch surface to move the cursor in theentire area of the relatively wide display surface.

The inventor of the present specification is examining to configure thetouch pad to allow detecting not only the touch position, but also acontact position of the pen (hereinafter, referred to as a “penposition”) on the touch surface.

However, after detailed examination for the realization of such a touchpad, the inventor of the present specification has found out that it isdifficult to normally input a line drawing even if the pen input can beperformed on the touch pad. More specifically, the position on the touchsurface and the position on the display surface need to correspondone-to-one in inputting the line drawing. However, such a relation isnot established in the relative coordinates used for the output of thetouch pad, and the line drawing cannot be normally input.

If the data supplied from the touch pad to the operating system ischanged from the relative coordinates to the above-described absolutecoordinates (in this case, coordinates in the coordinate system of thetouch surface), the pen can be used to input the line drawing for thetime being. However, the touch surface is generally much smaller thanthe display surface, and it is difficult to input a detailed linedrawing even in this configuration. Further, if the data supplied fromthe touch pad to the operating system is changed to the absolutecoordinates, the advantage of the relative coordinates as describedabove cannot be obtained, and this obstructs the control of the movementof the cursor with use of the finger.

BRIEF SUMMARY

Therefore, an object of the present disclosure is to provide a systemfor touch pad that can favorably realize both control of a cursor withuse of a finger and input of a line drawing with use of a pen.

The present disclosure provides a system for a touch pad used by both afinger and a pen to input operations to a computer. The system includesa sensor electrode group, an integrated circuit, and a memory storing adevice driver configured to be executed by the computer. The sensorelectrode group is configured to be placed over a touch surface that isdifferent from a display surface of the computer. The integratedcircuit, in operation, uses the sensor electrode group to detect a touchposition on the touch surface where the finger is in contact with thetouch surface and a pen position on the touch surface where the pen isin contact with the touch surface and supplies the detected touchposition and pen position to the device driver based on absolutecoordinates in a coordinate system of the touch surface. The devicedriver is configured to convert the touch position into relativecoordinates indicating a distance and a direction of movement of thetouch position and output the relative coordinates when the devicedriver receives the touch position from the integrated circuit. Thedevice driver is configured to convert the pen position into absolutecoordinates in a coordinate system of a logical region held by thecomputer at a time of reception of the pen position and output theabsolute coordinates when the device driver receives the pen positionfrom the integrated circuit.

According to the present disclosure, the device driver uses differentmethods according to the type of contact position (touch position or penposition) supplied from the integrated circuit to convert thecoordinates. This can favorably realize both control of a cursor withuse of a finger and input of a line drawing with use of a pen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a notebook computer according to a first embodiment ofthe present disclosure;

FIG. 2 depicts an internal configuration and functional blocks of thenotebook computer illustrated in FIG. 1;

FIG. 3 is a diagram illustrating, in chronological order, positiondetection performed by an integrated circuit illustrated in FIG. 2;

FIG. 4 is a flow chart illustrating details of a process performed by adevice driver illustrated in FIG. 2;

FIG. 5 is an explanatory diagram of decision of a logical regionperformed at S4 of FIG. 4;

FIG. 6A is an explanatory diagram of conversion performed at S5 of FIG.4, and FIG. 6B is an explanatory diagram of conversion performed at S10of FIG. 4;

FIG. 7A depicts a decision method of the logical region according to afirst modification of the first embodiment of the present disclosure,and FIG. 7B depicts a decision method of the logical region according toa second modification of the first embodiment of the present disclosure;and

FIG. 8 depicts a touch pad according to a second embodiment of thepresent disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will now be described in detailwith reference to the attached drawings.

FIG. 1 depicts a notebook computer 1 according to a first embodiment ofthe present disclosure. As illustrated in FIG. 1, the notebook computer1 is a portable computer and includes a housing 2, a touch pad 3including a touch surface T, a right click button 4, a left click button5, a keyboard 6, and a display 7 including a display surface H. Althoughthe right click button 4 and the left click button 5 are providedseparately from the touch surface T in the example of FIG. 1, the touchsurface T may be configured as click buttons.

FIG. 2 depicts an internal configuration and functional blocks of thenotebook computer 1. As illustrated in FIG. 2, the notebook computer 1includes an input-output circuit 11, a central processing unit (CPU) 12,and a memory 13 that are connected to one another through a bus 14.

The CPU 12 is a central processing unit of the notebook computer 1. Inone or more implementations, the CPU 12 includes a processor and aworking memory storing instructions that, when executed by theprocessor, cause the CPU 12 perform the functions described herein. TheCPU 12 plays a role of reading and executing programs stored in thememory 13. Examples of the programs executed in this way include variousapplications, such as an operating system of the notebook computer 1 anda drawing application, and device drivers of various types of hardware.FIG. 2 illustrates only a device driver 20 of the touch pad 3 amongthem.

FIG. 1 illustrates a state in which a cursor C and a document 100including a signature line 101 are displayed on the display surface H ofthe display 7. The CPU 12 executes the operating system to display thecursor C and executes a word processing application to display thedocument 100.

FIG. 2 will be further described, the memory 13 includes a storageapparatus including a main storage device, such as a dynamic randomaccess memory (DRAM), and an auxiliary storage device, such as a harddisk. Various programs executed by the CPU 12 and various types of datareferenced, generated, and updated by the various programs are stored inthe memory 13.

The input-output circuit 11 is a circuit that functions as an interfacefor connecting various types of hardware installed inside and outside ofthe notebook computer 1 to the CPU 12. Specifically, the input-outputcircuit 11 may include a circuit corresponding to a universal serial bus(USB) standard. Examples of the hardware connected to the CPU 12 throughthe input-output circuit 11 include the touch pad 3, the right clickbutton 4, the left click button 5, the keyboard 6, and the display 7 asillustrated in FIG. 2.

The right click button 4 and the left click button 5 are each a pressbutton switch that provides a click feeling to a user pressing thebutton and is used for inputting a click operation. The keyboard 6includes various keys including a plurality of letter keys, a pluralityof symbol keys, and a plurality of function keys. Information indicatingthe press of the right click button 4, the left click button 5, andvarious keys in the keyboard 6 is transmitted to the CPU 12 through theinput-output circuit 11.

The display 7 is a display apparatus including, for example, a liquidcrystal display or an organic electroluminescent (EL) display. Thedisplay 7 plays a role of displaying letters and images on the displaysurface H illustrated in FIG. 1 according to drawing data supplied fromthe CPU 12 through the input-output circuit 11.

The touch pad 3 includes a touch panel 30 and an integrated circuit 31.Of these, the touch panel 30 is a touch panel corresponding to acapacitance system. The touch panel 30 includes the touch surface T (seeFIG. 1) that is different from the display surface H of the notebookcomputer 1; and a sensor electrode group arranged just below the touchsurface T.

The touch surface T includes a plane suitable for the user to slide afinger F and a pen P illustrated in FIG. 1. Examples of specificstructure of the touch surface T include a simple flat plate that doesnot particularly have an electrical function and a structure, such aswhat is called Boogie Board (registered trademark), in which thetrajectory of the pen P is visualized on the touch surface T. The latterstructure will be described in detail in a second embodiment.

The sensor electrode group includes, for example, a plurality ofrectangular linear electrodes (hereinafter, referred to as“X-electrodes”) extending in a short-side direction of the touch surfaceT and a plurality of rectangular linear electrodes (hereinafter,referred to as “Y-electrodes”) extending in a long-side direction of thetouch surface T. The X-electrodes are arranged at equal intervals in thelong-side direction of the touch surface T, and the Y-electrodes arearranged at equal intervals in the short-side direction of the touchsurface T. However, the configuration of the sensor electrode group isnot limited to this, and the sensor electrode group can include, forexample, a plurality of island-like electrodes arranged in a matrix.

The integrated circuit 31 uses the above-described sensor electrodegroup to execute a process of detecting a touch position on the touchsurface T where the finger F is in contact with the touch surface T anddetecting a pen position on the touch surface T where the pen P is incontact with the touch surface T. Although the specific method ofdetecting the position is not particularly limited, it is preferable toadopt a detection method in which, for example, the detection of thetouch position based on the capacitance system and the detection of thepen position based on the active capacitive system are performed in timedivision. The touch position and the pen position detected by theintegrated circuit 31 are supplied to the device driver 20 through theinput-output circuit 11. In this case, the data actually supplied fromthe integrated circuit 31 to the device driver 20 includes absolutecoordinates in the coordinate system of the touch surface T.

FIG. 3 is a diagram illustrating, in chronological order, the positiondetection performed by the integrated circuit 31. As illustrated in FIG.3, the integrated circuit 31 is configured to detect the touch positionand the pen position in time division.

FIG. 3 illustrates an example of a case in which the user moves thecursor C to the signature line 101 illustrated in FIG. 1 and causes theoperating system to provide input focus to the signature line 101 beforetime t1, and the user then writes the name of the user in the signatureline 101 from time t2 to time t3.

In the example, the user first slides the finger F on the touch surfaceT to move the cursor C to the signature line 101. The user presses theleft click button 5 illustrated in FIG. 1 to causes the operating systemto provide input focus to the signature line 101 (before time t1).Meanwhile, only the touch position is continuously output from theintegrated circuit 31, and the pen position is not output.

Subsequently, the user holds the pen P in hand and inputs the name ofthe user on the touch surface T (time t2 to time t3). Meanwhile, onlythe pen position is continuously output from the integrated circuit 31,and the touch position is not output.

FIG. 2 will be further described. The device driver 20 is a programincluded in a system for touch pad along with the sensor electrode groupin the touch panel 30, the integrated circuit 31, and the like. Thedevice driver 20 causes the CPU 12 to perform various types ofprocessing including touch position conversion processing 21 and penposition conversion processing 22. The touch position conversionprocessing 21 converts the coordinates indicating the touch positionsupplied from the integrated circuit 31 (absolute coordinates in thecoordinate system of the touch surface T) into relative coordinatesindicating the distance and the direction of movement of the touchposition and outputting the relative coordinates. On the other hand, thepen position conversion processing unit 22 converts the coordinatesindicating the pen position supplied from the integrated circuit 31(absolute coordinates in the coordinate system of the touch surface T)into absolute coordinates in the coordinate system of a logical regionheld at the time of the supply of the pen position (any region in thedisplay surface H set by a user operation, which will be described indetail later) and outputting the absolute coordinates.

FIG. 4 is a flow chart illustrating details of a process performed bythe device driver 20 while the CPU 12 executes the device driver 20. Theprocess performed by the device driver 20 will be described in detailwith reference to FIG. 4.

As illustrated in FIG. 4, the device driver 20 first monitors generationof an interrupt from the touch pad 3 (S1). If there is an interrupt fromthe touch pad 3, the device driver 20 determines which one of the penposition and the touch position is included in the data supplied fromthe touch pad 3 (S2).

If the device driver 20 determines that the pen position is included inthe data at S2, the device driver 20 determines whether or not thelogical region is already decided (S3). If the device driver 20determines that the logical region is not decided yet, the device driver20 decides the logical region based on a window region having inputfocus by the operating system (S4). The device driver 20 stores thelogical region decided at S4 in the memory 13 illustrated in FIG. 2.

FIG. 5 is an explanatory diagram of the decision of the logical regionperformed at S4. FIG. 5 illustrates an example in which the operatingsystem displays a window region W1 including a sub-window region W2 onthe display 7. The sub-window region W2 is, for example, the signatureline 101 illustrated in FIG. 1.

It is assumed that the sub-window region W2 has input focus based on auser operation. The device driver 20 decides a logical region R so as toinclude the entire sub-window region W2. More specifically, the devicedriver 20 sets a logical region R1 including the long side in the samelength as the length of the long side of the rectangular sub-windowregion W2 and having the same orientation and aspect ratio as those ofthe touch surface T. The device driver 20 sets a logical region R2including the short side in the same length as the length of the shortside of the rectangular sub-window region W2 and having the sameorientation and aspect ratio as those of the touch surface T. The devicedriver 20 sets, as the logical region R, one of the two logical regionsR1 and R2 (logical region R1 in FIG. 5) including the entire sub-windowregion W2 when the logical regions R1 and R2 are aligned at the centerof the sub-window region W2. However, when the aspect ratios do not haveto be equal (that is, when the line drawing depicted on the touchsurface T may be vertically or horizontally extended on the displaysurface H), the device driver 20 may set the sub-window region W2 as thelogical region.

FIG. 4 will be further described. If the device driver 20 decides thelogical region at S4 or determines that the logical region is alreadydecided at S3, the device driver 20 converts the pen position suppliedfrom the integrated circuit 31 into absolute coordinates in thecoordinate system of the decided logical region and outputs the absolutecoordinates (S5).

FIG. 6A is an explanatory diagram of the conversion performed at S5.Absolute coordinates (X, Y) output at S5 are expressed by Equation (1)below, where the touch surface T is a region of x=0 to x_(M), y=0 toy_(M), and the logical region R is a region of X=0 to X_(M), Y=0 toY_(M) as illustrated in FIG. 6A.

(X,Y)=(x×X _(M) /x _(M) ,y×Y _(M) /y _(M))  (1)

FIG. 4 will be further described. The device driver 20 that has outputthe absolute coordinates at S5 returns to S1 and monitors the generationof an interrupt from the touch pad 3. While monitoring, the devicedriver 20 measures the passage of time from the supply of the penposition of the last time. If the logical region decided at S4 is stillheld in the memory 13 when a predetermined time has passed, the devicedriver 20 releases the logical region (S6 and S7). That is, the devicedriver 20 deletes the logical region from the memory 13. After this, thedetermination result of S3 returns to “not decided yet.”

When the device driver 20 determines that the touch position is includedin the data at S2, the device driver 20 releases the logical region asat S7 if the logical region is held in the memory 13 at that point (S8)and then acquires the touch position or the pen position supplied justbefore the touch position of this time (S9). The device driver 20converts the touch position supplied this time into relative coordinatesindicating the distance and the direction from the position acquired atS9 and outputs the relative coordinates (S10).

FIG. 6B is an explanatory diagram of the conversion performed at S10. Apoint P_(O) illustrated in FIG. 6B is a position acquired at S9, and apoint P_(N) is a position supplied at S1. A vector V illustrated in FIG.6B is a vector starting at the point P_(O) and ending at the pointP_(N). The relative coordinates obtained as a result of the conversionat S10 are expressed as (V_(x), V_(y)), where V_(x) is an x-directioncomponent of the vector V, and V_(y) is a y-direction component of thevector V.

FIG. 4 will be further described. The device driver 20 that has outputthe relative coordinates at S10 returns to S1 and monitors thegeneration of an interrupt from the touch pad 3. The device driver 20then repeats the process described above.

As described above, according to the system for touch pad of the presentembodiment, the device driver 20 uses different methods according to thetype of contact position (touch position or pen position) supplied fromthe integrated circuit 31 to convert the coordinates. Therefore, thesystem for touch pad can favorably realize both the control of thecursor with use of the finger F and the input of a line drawing with useof the pen P.

In addition, according to the system for touch pad of the presentembodiment, the touch position is output based on the relativecoordinates indicating the distance and the direction of movement of thetouch position. Therefore, the control of cursor similar to theconventional touch pad can be realized by the finger F.

Further, according to the system for touch pad of the presentembodiment, the pen position is output based on the absolute coordinatesin the coordinate system of the logical region held by the device driver20 at the time of the supply of the pen position. Therefore, the pen Pcan be used to favorably input a line drawing in any region of thedisplay surface.

In addition, according to the system for touch pad of the presentembodiment, the pen position is regarded as a start point in detectingthe relative coordinates when the touch position is detected followingthe pen position. Therefore, the cursor can be moved from the positionon the display surface H designated lastly by the pen P.

Although the logical region is decided based on the window region havinginput focus by the operating system in the example described in theembodiment, the device driver 20 can use other methods to decide thelogical region. Two examples of the methods will be described.

FIG. 7A depicts a decision method of the logical region according to afirst modification of the present embodiment. The device driver 20according to the present modification is configured to decide thelogical region based on the window region including the cursor C of thenotebook computer 1. In the example of FIG. 7A, two window regions W1and W2 are displayed on the display surface H, and the cursor C isincluded in the window region W1 on the back side with respect to thewindow region W2. Therefore, the device driver 20 decides the logicalregion R based on the window region W1 at S4 of FIG. 4. As a result, thelogical region R can also be decided based on the window region on theback side (window region not having input focus).

Although part of the logical region R overlaps the window region W2 inthe example of FIG. 7A, the device driver 20 can output the absolutecoordinates indicating the pen position in the region as usual. Theoperating system or the application receiving the absolute coordinatesfrom the device driver 20 can appropriately decide whether or not toallow displaying the line drawing in the window region W2.

FIG. 7B depicts a decision method of the logical region according to asecond modification of the present embodiment. The device driver 20according to the present modification is configured to decide thelogical region based on the region set on the display surface H througha user operation or an application. In the example of FIG. 7B, a regionU (region surrounded by a dashed line) is set through a user operationor an application in the window region W1 displayed by one of theapplications, and the device driver 20 according to the presentmodification is configured to decide the logical region R based on theregion U at S4 of FIG. 4. As a result, the logical region R can also bedecided based on any region that is not a window region.

Note that the specific method of setting the region U is notparticularly limited. For example, the user may set the application to alogical region setting mode and move the cursor in a diagonal directionto set the region U. The user may designate numerical values of thevertical length, the horizontal length, and the position in a menuscreen of the application to set the region U.

Next, the system for touch pad according to a second embodiment of thepresent disclosure will be described. The system for touch pad accordingto the present embodiment is different from the system for touch padaccording to the first embodiment in that the touch surface T includes astructure that visualizes the trajectory of the pen P on the touchsurface T. The system for touch pad according to the second embodimentis similar to the system for touch pad according to the first embodimentin other respects. Therefore, the same reference signs are provided tothe same components, and the difference from the system for touch padaccording to the first embodiment will be mainly described.

FIG. 8 depicts the touch pad 3 according to the present embodiment. Asillustrated in FIG. 8, the touch pad 3 according to the presentembodiment is different from the touch pad 3 according to the firstembodiment in that, in the touch pad 3 according to the presentembodiment, the touch panel 30 includes a pressure-sensitive display 30Aand a sensor electrode group 30B, and the right click button 4 and theleft click button 5 also described in the first embodiment are includedas components of the touch pad 3.

The touch surface T according to the present embodiment is provided by adisplay surface of the pressure-sensitive display 30A. Thepressure-sensitive display 30A is a display in which, when pressureequal to or greater than a predetermined threshold is applied to pressthe display surface, the color of the part changes. The threshold of thepressure that changes the color is set to a value smaller than thepressure applied to the touch surface T by the pen P and greater thanthe pressure applied to the touch surface T by the finger F. Therefore,the pressure-sensitive display 30A can selectively display thetrajectory of the pen P on the touch surface T.

Further, the pressure-sensitive display 30A can also apply a current ofa predetermined value to a predetermined terminal to reset the display.The color of the reset display surface of the pressure-sensitive display30A as a whole returns to the color before the press of the displaysurface with use of the pressure equal to or greater than thepredetermined threshold. Therefore, the user can use the pen P to writea new entry on the touch surface T not displaying anything.

The configuration of the sensor electrode group 30B is the same as theconfiguration of the sensor electrode group described in the firstembodiment. The right click button 4 and the left click button 5 havethe configurations and roles described in the first embodiment. However,the right click button 4 and the left click button 5 according to thepresent embodiment are connected to the input-output circuit 11 throughthe integrated circuit 31.

The integrated circuit 31 has the function described in the firstembodiment. In addition, the integrated circuit 31 is configured tosupply information indicating the press of the right click button 4 orthe left click button 5 to the input-output circuit 11 and apply thepredetermined current to the predetermined terminal of thepressure-sensitive display 30A when the button is pressed. Therefore,the right click button 4 and the left click button 5 according to thepresent embodiment also serve as bulk delete buttons for deleting thedisplay of the pressure-sensitive display 30A at once.

As described above, according to the present embodiment, the trajectoryof the pen P is displayed on the touch surface T. Therefore, the usercan use the pen P to input an entry while visually checking the writtencontent on the touch surface T, and the user can more comfortablyperform the pen input on the touch surface T.

The pressure-sensitive display 30A is used, and therefore, thetrajectory of the pen P can be displayed on the touch surface T with asimpler configuration than in a case of using a liquid crystal displayor the like.

Although the right click button 4 and the left click button 5 also serveas bulk delete buttons in the example described in the presentembodiment, only one of the right click button 4 and the left clickbutton 5 may serve as a bulk delete button, or a bulk delete button maybe provided separately from the right click button 4 and the left clickbutton 5.

Although the preferred embodiments of the present disclosure have beendescribed, the present disclosure is not limited to the embodiments inany way, and it is obvious that the present disclosure can be carriedout in various modes without departing from the scope of the presentdisclosure.

For example, although the present disclosure is applied to the touch padof the notebook computer in the examples described in the embodiments,the present disclosure can also be widely applied to touch pads providedon apparatuses other than the notebook computer.

Although the method of coordinate conversion performed by the devicedriver 20 is changed according to the type of contact position in theembodiments, the method of coordinate conversion performed by the devicedriver 20 may be changed based on the user setting on a freely-selectedapplication or operating system. In this way, the user can use thefinger F to input a line drawing or use the pen P to control the cursoras the user wishes.

Although the device driver 20 executed by the CPU 12 converts thecoordinates in the embodiments, the coordinates may be converted in theintegrated circuit 31. In this case, it is preferable to supplyinformation regarding the logical region from the device driver 20 tothe integrated circuit 31.

It is to be noted that the embodiment of the present disclosure is notlimited to the foregoing embodiment, and that various changes can bemade without departing from the spirit of the present disclosure.

What is claimed is:
 1. A system for a touch pad used by both a fingerand a pen to input operations to a computer, the system comprising: asensor electrode group; an integrated circuit; and a memory storing adevice driver configured to be executed by the computer, wherein: thesensor electrode group is configured to be placed over a touch surfacethat is different from a display surface of the computer, the integratedcircuit, in operation, uses the sensor electrode group to detect a touchposition on the touch surface where the finger is in contact with thetouch surface and a pen position on the touch surface where the pen isin contact with the touch surface and supplies the detected touchposition and pen position to the device driver based on absolutecoordinates in a coordinate system of the touch surface, the devicedriver is configured to convert the touch position into relativecoordinates indicating a distance and a direction of movement of thetouch position and output the relative coordinates when the devicedriver receives the touch position from the integrated circuit, and thedevice driver is configured to convert the pen position into absolutecoordinates expressed by a coordinate system of a logical region held bythe computer at a time of reception of the pen position and output theabsolute coordinates when the device driver receives the pen positionfrom the integrated circuit.
 2. The system according to claim 1, whereinthe device driver is configured to determine the logical region based ona window region including a cursor of the computer.
 3. The systemaccording to claim 2, wherein the device driver is configured to causethe computer to release the logical region when the integrated circuitstops supplying the pen position for a predetermined period.
 4. Thesystem according to claim 2, wherein the device driver is configured tocause the computer to release the logical region when the device driverreceives the touch position from the integrated circuit.
 5. The systemaccording to claim 1, wherein the device driver is configured todetermine the logical region based on a region set on the displaysurface through a user operation or an application.
 6. The systemaccording to claim 1, wherein the device driver is configured todetermine the logical region based on a window region having input focusby an operating system of the computer.
 7. The system according to claim6, wherein the logical region determined by the device driver includesall of the window region.
 8. The system according to claim 1, whereinthe device driver is configured to regard the pen position as a startpoint in detecting the relative coordinates when the device driverreceives the touch position after the pen position.
 9. The systemaccording to claim 1, wherein the touch surface includes a displaysurface of a pressure-sensitive display which, in operation, displays atrajectory of the pen.
 10. The system according to claim 9, wherein: thetouch pad includes a button which, in operation, causes the trajectorydisplayed on the display surface of the pressure-sensitive display to bedeleted, and also causes a click operation to be input to the computer.